Guide assembly for washover pipe



Oct. 25, 1960 G. E. KEMNITZ GUIDE ASSEMBLY FOR wAsHovER PIPE 2 Sheets-Sheet 1 Filed Feb. ll, 1957 IN V EN TOR.

, iam

ATTORNEYS @SORGE E. KEM/V/TZ Oct. 25, 1960 G. E. KEMNITZ GUIDE ASSEMBLY FOR WASHOVER PIPE 2 Sheets-Sheet 2 Filed Feb. ll, 1957 B g, Lm

GUIDE ASSEMBLY FOR WASHOVER PIPE George E. Kernnitz, Tulsa, Okla., assignor to Noble Drilling Corporation, Tulsa, Okla., a corporation of Delaware Filed Feb. 11, 1957, Ser. No. 639,354

3 Claims. (Cl. 166.221)

This invention relates to new and useful improvements in guide apparatus for washover operations.

When a drill collar or pipe becomes stuck Within a well bore, it is the general practice to lower a washover pipe downwardly around the stuck element or fish to carry out a washover operation. The lower end of the washover pipe has a rotary shoe or cutting tool secured thereto and generally the washover pipe is rotated simultaneously with the circulation of the washing uid, the rotary shoe functioning to cut out or drill any material or debris has lodged about the stuck element.

Where the stuck element is a large drill collar or a pipe having relatively small clearance with respect to the wall of the well bore, ditliculty is experienced in locating the washover pipe in encircling relationship to the stuck element and in many instances, the rotation of the washover pipe results in the rotary shoe actually cutting the upper end of the stuck element. This damages the threaded connection, usually a box, at the upper end of the ,stuck element to the extent that it is impossible to subsequently make reconnection with a removing pipe string after the stuck element has been loosened. In the case `of a drill collar, damage to one end thereof destroys lthe collar and as is well known, the usual drill collar is quiterexpensive.

lt is, therefore, one object of this inventionto provide an improved guide apparatus which may be readily conn nected to a stuck element, such as a drill collar or pipe, and which has means for guiding a subsequently lowered washover pipe into proper position encircling the stuck element, whereby etiicient washover operations may be carried out even though there be small annular clearance between the stuck pipe and the wall of the well bore.

An important object is to provide a guide apparatus `adapted to be connected to the upper end off a stuck element which not only guides the washover pipe into proper position, but also protects the upper end of the stuck element against any possible damage by reason of rota- -tion of the usual rotary shoe.

Another object is to provide a guide apparatus consisting of an upper sub member and a lower sub member which are releasably connected to each other; said sub members being lowered into the well bore in connected position and being manipulated by means of the lowering pipe to iirst attach the lower sub member to the stuck element and to thereafter disconnect the sub members from each other, whereby the upper sub member may be removed from the -well bore while the lower sub member remains attached to the stuck element and functions as a lguide for guiding `a washover pipe into proper position over the stuck element, said lower sub member having means at its upper end for subsequently attaching a removing pipe thereto, whereby the stuck element may be retrieved after it has been loosened by the washover operation.

The construetlon designed to carry out the invention 2,957,525 Patented Oct. 25, 1960 will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

Figure l is a view illustrating a drill collar stuck within a well bore and showing the guide apparatus, constructed in laccordance with 4the invention, being lowered downwardly through the well bore.

Figure 2 is a view similar to Figure 1 and showing the Ilower sub member of the guide apparatus in connected or attached position with the drill collar and illustrating the upper sub member of said apparatus being removed frorn the well bore.

Figure 3 is a similar view lshowing a washover pipe in position encircling the upper end of the stuck drill collar.

Figure 4 is a View similar to Figures -1 -to 3 and show ing a retrieving pipe connected with the lower sub member of the apparatus and illustrating the manner of removal of the drill collar after it has been loosened from -its stuck position and Figure 5 is a transverse vertical sectional view of the guide apparatus, constructed in accordance with this invention.

In the drawings the letter W indicates a well bore within which a drill collar D is illustrated as being stuck, with material or debris y10 surrounding the drill collar and maintaining it in its stuck position. The drill collar D has the usual threaded box 11 in its upper end which box was previously connected with a drill pipe, such drill pipe having been removed when the drill collar and the portion therebelow (not shown) became stuck in the well.

The guide apparatus of the present invention is generally indicated by the letter A and this apparatus is connected to the lower end of a lowering pipe 12. Referring to Figure 5, the apparatus A includes a lower sub member or body 13. The lower end of the body is formed with a threaded pin 14, the external threads of which are adapted to tit the threaded box 11 of the drill collar D. A vertical circulation passage or bore 15 extends entirely through the member or body 13.

At its upper portion, the bore or passage 15 of the lbody 13 is enlarged as indicated at 16 and this forms an internal annular shoulder 17 within the body. Threads 1S are formed within the portion 16 of the passage. Above the enlarged portion 16, the bore or passage 15 of the body is further enlarged and is preferably tapered to form a threaded box 19. The threads of the box 19 are preferably the usual connecting threads which will connect with the ordinary pin on drill pipe of a particular size. The threads 18, which are formed within the enlarged portion 16 belowthe box 19, are preferably left-hand threads and are adapted to be engaged by the threads 20 formed on a depending pin Z1 at the lower end of an upper sub member 22. Immediately above the threads 20, the pin 2.1 is tapered as shown at 23, and this tapered portion terminates in a shoulder 24. The outer diameter of the upper sub member 22 is substantially equal to the external diameter 13-a at the upper end of the body or lower sub member 13. As is clearly shown in Figure 5, the external diameter of the portion 13-a is smaller than the external diameter 13-b of the main portion of the body 13, these diiferent diameter portions being connected by a taper or bevel section 13o-0.

In using the improved apparatus, the upper sub 22 is connected to the lower sub or body 13 by means of the threads 20 on pin 21 engaging the threads 18 within the portion 16 of the bore of the body. As has been noted, this is a left-hand threaded connection. The location of the external shoulder 24 on the upper submember 22 is such that when the threads 20 are made up with Vthe threads 1S, shoulder 24 abuts or engages the upper end 13d of the body 13. This is the position of the parts as illustrated in Figure l, and it is noted that at this time the tapered portion 23 of the pin 21 is disposed within the box 19, although, of course, it is not engaged with the threads of said box. i

The upper sub member has a threaded box 25 to which is `connected a lowering pipe 12, and the apparatus is thus lowered into the well bore in the manner shown in Figure 1. Upon the engagement of the threaded pin 14 on the lower sub member or body 13 with the threaded box V11 of the drill collar D, the lowering pipe 12 is rotated in a direction to the right to make up the pin 14 into the box 11. In this regard it is noted that when the left-hand threads 18 and 2) are connected, they are made up relatively tight, so that a right-hand rotation of the lowering pipe will result in a connection of the pin 14 to the box 11 before there is any breaking out or disconnection of threads 18 and 20. After the lower sub member or body 13 is connected to the drill collar D, continued rotation to the right will break out the threads 18 and 20 and will disconnect the upper sub member 22 from the body 13. Thereafter, the lowering pipe 12 may be lifted upwardly in the manner illustrated in Figure 2 and the lowering pipe, together with the upper sub member 22, may be removed from the well bore. This leaves the lower sub member or body 13 having its upper end reduced at 13-11, located in attached position in the well bore. It is pointed out that the major portion of the body 13 has its diameter 13-b substantially equal to the external diameter of the drill collar. Thus, an external shoulder 14-a formed on the body 13 just above the pin 14 will engage the upper end of the drill collar D and will thereby protect and completely cover such upper end.

After the lowering pipe and the upper sub member 22 have been removed from the well bore, a washover pipe 30 may be lowered by means of a suitable lowering pipe 31. This washover pipe normally has a rotary shoe 32 secured thereto and, as is well known, it is necessary that the washover pipe encircle the drill collar, moving downwardly through the annular space S between the exterior of the drill collar and the wall of the well. Since the upper portion 13-a of the body 13 is of substantially less diameter than the diameter of the drill collar D, it is evident that as the wash pipe 30 is lowered, it will be guided over the reduced portion 134er very readily. This portion 13-a of the body 13 then functions to center the washover pipe and to guide said pipe downwardly along the inclined portion 13-6 and in encircling relationship to the main portion 13-b of the body 13. The washover pipe is thus readily guided into proper encircling relationship with respect to the upper end of the drill collar and upon the subsequent rotation of the washover pipe, the rotary shoe will properly drill out the material or debris which is holding the drill collar in stuck position. It is evident that, not only does the body 13 guide the washover pipe into proper position around the drill collar, but at the same time said body fully covers and protects the upper end of the drill collar from any damage by rotation of the rotary shoe, as might be the case if it is attempted to place the washover pipe directly over the drill collar.

After the washover operation is complete, it is only necessary to remove the washover pipe and to then lower a retrieving pipe 33, and connect the lower end of said retrieving pipe intoV the threaded box 19 at the upper end of the body 13, in the manner illustrated in Figure 4. When this is done, the retrieving pipe 33 may be utilized to remove the loosened drill collar D from the well bore.

Upon reaching the surface, the body 13 is, of course, disconnected from the drill collar and is reconnected to the upper sub member 22 so 'as to be ready for a subsequent operation.

From the foregoing it will be seen that a simple apparatus is provided which may be readily lowered into the well bore and attached to a stuck element or iish, after which a portion of the apparatus is removed so as to expose a connection, such :as the threaded box 19, whereby a `retrieving pipe may be subsequently connected thereto in order to remove the device and the stuck element from the well bore. It has been found that the left-hand connection between threads 20 on the pin 21 and the threads 18 is a satisfactory way of releasably connecting the upper sub member 22 to the body 13. However, it is pointed out that other types of releasable connections could be employed. For example, a well known J-slot and a pin connection could be made between the parts. Such a J-slot and pin connection would releasably secure the upper sub member 22 to the body 13 and would permit rotation of the body 13 in order to connect its pin 14 with the drill collar; yet at the same time, it would be possible, after the connection is made, to uncouple the upper sub member 22 from the body 13, whereby said body would remain in the well bore to guide the washover pipe into proper encircling relationship to the stuck element.

The particular proportions and sizes of the various parts of the apparatus are, of course, subject to some variation. For example, the reduced guide section or portion 13-a of the body could be increased in length over that illustrated and also the longitudinal extent of the tapered portion 13-c could be increased and its taper made more gradual than that shown. It is preferable that the lower portion of the body 13 at the shoulder 14-a have substantially the same diameter as the drill collar or the stuck element, so as to protect the upper end thereof although it could be slightly smaller and still accomplish the purpose. If desired, the external diameter of the body could be gradually tapered from shoulder 14-a to its upper end 13-d so that the body would, in effect, be tapered from end to end and such arrangement would produce a satisfactory guiding of the washover pipe into proper relationship to the drill collar. It is noted that the upper sub member 22 is also formed with the bore or passage 22-a, which extends completely therethrough so that circulation completely through the apparatus may be maintained as the same is being lowered downwardly into the well bore and during the time that the connection of the pin 14 is made with the drill collar.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made within the scope of the appended claims without departing from the spirit of the invention.

What l claim is:

1. A well apparatus adapted to coact with a tubular stuck element within a well bore wherein the stuck element has a threaded box in its upper end, said apparatus including, an elongate tubular tbody having a threaded pin at its lower end for connection with the box of the stuck element, a reduced external guide portion formed at the upper end of the `:body and having an internally threaded box for receiving a retrieving pipe, an upper sub member having its upper end attached to a lowering pipe, and means for releasably connecting said upper sub member to the tubular body, lwhereby said member and body may be lowered into the well bore as a unit and the body attached to the stuck element after which the upper sub member may be disconnected from said body and removed from the well by means of the lowering pipe.

2.V A well apparatus as set forth in claim 1, wherein both the body and the upper sub member have uid passagesV extending axially therethrough.

5 3. A well apparatus as set forth in claim 1, wherein the means for releasably connecting the upper sub member to the -body `comprises internal left-hand threads formed with the body below the threaded box and an external left-hand threaded pin formed on the lower end 5 of the upper sub member.

References Cited in the le of this patent UNTTED STATES PATENTS 2,051,713 Howard Aug.1s,1936 10 Singleton Feb. 8, 1938 Phillips Oct. 15, 1940 Kemnitz Feb. 20, 1951 Jacobson Dec. 9, 1952 Stewart July 28, 1953 Clayton June 14, 1955 Naylor Sept. 11, 1956 Hall Sept. 3, 1957 

